Assessment of Water Quality, Diet and Fish Community in Selected Inland Waters in Katsina State, Nigeria

Abstract

ABSTRACT

Katsina State is blessed with diverse aquatic ecosystems which provide essential water resources for irrigation, domestic use, and fisheries. This study investigates the impact of water quality on diet composition and fish com munities in three inland water ecosystems: Zobe (Sudan savanna), Sabke (Sahel savanna), and Mairuwa reservoirs (Guinea savanna) conducted from October 2023 to July 2024. Water and fish samples were collected from three different sites. The study assessed various water quality parameters to elucidate their effects on fish diet and abundance in the ecosystems. The results revealed that there was no significant difference in mean temperature and pH values (p˃0.05) across the study sites. However, there was significant difference in Electrical conductivity, Dissolve oxygen, Biological oxygen demand, Turbidity, Hardness, Chemical oxygen demand, Total dissolve solids and Total suspended solids mean values (p˂0.05). Sabke reservoir exhibited the highest populations of fish species 243 Oreochromis niloticus and 250 Lates niloticus, which was attributed to favourable environmental conditions. In contrast, Mairuwa reservoir demonstrated greater biodiversity, as indicated by a higher Margalef diversity index 0.8142. Also identified negative correlations in length-weight relationships (allometric growth) for several fish species across the Zobe, Sabke, and Mairuwa reservoirs. Dietary preferences among fish species revealed that Schilbe mystus mainly consumes insects, with rates of 56.6%, 63.3%, and 43.3% in the Zobe, Sabke, and Mairuwa reservoirs, respectively. Clarias gariepinus primarily feeds on larger prey, notably fish parts, with 13.3% in Zobe, 70.0% in Sabke, and 46.6% in Mairuwa. Findings showed Lates niloticus as an apical predator in the Sabke reservoir, consuming 90.0% fish parts. Meanwhile, Bagrus bayad in the Mairuwa reservoir prefers fish, making up 63.3% of its diet. Further studies needed to investigate the interactions among water quality, fish diversity, and habitat conditions in freshwater ecosystems